An upcoming event at the Indian Creek Nature Center prompted me to call one of our awesome entomologists at Iowa State University. The Nature Center is having a walk at 8 p.m. Friday featuring one of my favorite insects – the lightning bug!

Lightning bug/ David Cappaert, Michigan State University, Bugwood.org

What’s not to love about lightning bugs? They light up dark summer nights with their intermittent flashes and unlike other nighttime bugs, they don’t bite – in fact, they kind of tickle when you catch them. Best of all, in their younger stage, they eat slugs and other pests.

I wrote about lightning bugs last year after attending a workshop led by ISU entomologist Donald Lewis. Until then, I had no idea that lightning bugs, as larvae, dined on not only slugs, but other insect larvae and snails – a real beneficial beetle! But I’ve had a nagging question since then: what do adult lightning bugs eat? After all, kids catch lightning bugs all the time, put them in a jar, punch holes in the lid and throw some grass inside. So do lightning bugs eat grass??

Probably not, was the answer. Donald Lewis said, if anything, they might occasionally feed on nectar. Some female species of lightning bugs use the signal of a different variety of lightning bug to attract males, and then, well, the male doesn’t become their mate, but their meal! So, that’s what that species eats, but, he said, most adult lightning bugs appear to not eat much of anything.

As an aside, he noted that punching holes in the lid of a jar might be more harmful to lightning bugs than leaving the lid intact and not-too-tight on the jar. Lightning bugs come out at night because they need a certain level of humidity and would basically dry up in the hot summer sun. Punching holes might allow too much air into the jar and also dry out the bugs. Safest bet might be a catch and release method. Get a good look, admire their flashing lights and let them fly free.

REMINDER: Remember to stop by the Gazette/KCRG tent between 9-10 a.m. Saturday (June 6, 2009) at the Downtown Farmers Market in Cedar Rapids. Sign up for the drawing (rattles, corn-made dishes and other baby items courtesy of Dandelion Earth Friendly Goods) and let me know what you’d like to see on the Homegrown blog and in The Gazette. The tent will be in Greene Square Park, along 4th Avenue, close to the corner along the railroad tracks. See you there!